1. Field of the Invention
The present invention pertains to resin compositions which are stabilized against degradation and/or discoloration by an effective amount of an aromatic ketone compound, including adducts and derivatives of an aromatic ketone compound. The resin compositions may optionally contain a stabilizer or mixture of stabilizers of at least one stabilizer selected from the group consisting of the phenolic antioxidants, the 3-arylbenzofuranones, the hindered amine stabilizers, the ultraviolet light absorbers, the tertiary amine oxides, the organic phosphorus compounds, the alkaline metal salts of fatty acids, the hydrotalcites, the epoxydized soybean oils, the hydroxylamines, the tertiary amine oxides, thermal reaction products of tertiary amine oxides, and the thiosynergists.
2. Brief Description of the Related Art
Although various antioxidants have long been known to be effective stabilizers for polymeric resins and have enjoyed wide commercial success for that use, these same stabilized polymeric resin compositions continue to degrade during high temperature processing such as during compounding and processing into articles of commerce.
While the addition of organic phosphites to such resin compositions stabilized with phenolic antioxidants tends to reduce the degradation, it remains a serious practical problem.
Likewise polymeric resin compositions containing certain phenolic antioxidants and hindered amine stabilizers tend to degrade, especially when subjected to repeated extrusions. Although such stabilized resin compositions are improved, there continues to exist a need and desire to provide polymeric resin compositions which exhibit enhanced levels of stability and to provide alternate stabilizer compositions for incorporation into polymer compositions.
Aromatic ketones, e.g., 2-bromo-9-anthrone and 2-ethyl-9-anthrone, have been reported as useful as sensitizers to increase the photopolymerization rate of photosensitive compounds, e.g. oxadiazole compounds, when used in combination with a photoinitiator. Skin conditions such as warts and psoriasis have also been treated with 1,8-dihydroxy-anthrone.
The use of aromatic ketones, as well as adducts and derivatives of aromatic ketone compounds, until this time as stabilizer additives for polymeric resins, however, is believed to be novel, especially when used in combination with other additives.